Path Sum II

Desciption:

Given a binary tree and a sum, find all root-to-leaf paths where each path’s sum equals the given sum.
For example: Given the below binary tree and sum = 22,

return

代码：

#include <iostream>
#include <vector>
#include <stack>
#include <algorithm>


#define Elementype int

using namespace std;

int index = 0;


typedef struct TreeNode //树结点
{
    Elementype  val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(Elementype x) : val(x), left(nullptr), right(nullptr) {}
} *Tree;


//使用先序遍历创建创建二叉树
void MakeBinaryTree(Tree &T, Elementype value[])
{
    Elementype  c = value[index++];
    if (c == '#')
        T = nullptr;
    else
    {
        T = new TreeNode(c);
        MakeBinaryTree(T->left, value);
        MakeBinaryTree(T->right, value);
    }

}


//先序遍历
void preOrderTraversal(Tree root)
{
    stack<Tree> sk;
    Tree p = root;
    if (p)
        sk.push(p);
    while (!sk.empty())
    {
        p = sk.top();
        cout << p->val<<" ";
        sk.pop();

        if (p->right)
            sk.push(p->right);

        if (p->left)
            sk.push(p->left);
    }
}
void pathSum(Tree root, int sum, vector<vector<int>> &result, vector<int> curVec)
{
    if (!root)
        return;
    curVec.push_back(root->val);
    if (root->left == nullptr && root->right == nullptr && sum == root->val)
        result.push_back(curVec);
    pathSum(root->left, sum - root->val, result, curVec);
    pathSum(root->right, sum - root->val, result, curVec);
}

vector<vector<int>> pathSum(Tree root, int sum)
{
    vector<vector<int>> result;     //保存结果
    vector<int> curVec;             //当前查找的路径
    pathSum(root, sum, result, curVec);
    return result;
}

int main()
{
    Tree root = nullptr;        //根结点
    Elementype data[] = { 5, 4, 11, 7,'#','#',2,'#','#','#', 8, 13, '#', '#', 4, 5,'#','#', 1,'#','#'};
    MakeBinaryTree(root, data);

    cout << "先序遍历： ";
    preOrderTraversal(root);
    cout << endl;

    int sum = 22;
    vector<vector<int>> path = pathSum(root, sum);

    for (auto i : path)
    {
        cout << "路径有： ";
        for (auto j : i)
            cout << j << " ";
        cout << endl;
    }

    system("pause");
    return 0;
}

测试：